Guidelines for Treating Urinary Tract Infections (UTIs)
First-line treatment for uncomplicated UTIs includes nitrofurantoin 100mg twice daily for 5 days, trimethoprim-sulfamethoxazole (TMP-SMX) 160/800mg twice daily for 3 days (if local resistance <20%), or fosfomycin 3g single dose. 1
Diagnosis of UTIs
Uncomplicated UTI can be diagnosed based on:
- Symptoms: new onset dysuria, urinary frequency, urgency, nocturia, suprapubic discomfort
- Urinalysis: moderate to large leukocytes and positive nitrites 1
Acute pyelonephritis is characterized by:
- High fevers and chills
- Dysuria and frequency
- Unilateral flank pain
- Nausea with or without vomiting
- Costovertebral angle tenderness
- WBC casts and proteinuria on urinalysis 1
Pyuria (≥10 WBCs/high-power field) or positive leukocyte esterase test indicates need for urine culture with antimicrobial susceptibility testing before starting treatment 1
Treatment Recommendations by UTI Type
Uncomplicated UTIs
First-line options:
- Nitrofurantoin 100mg twice daily for 5 days
- TMP-SMX 160/800mg twice daily for 3 days (if local resistance <20%)
- Fosfomycin 3g single dose 1
Short-course therapy (3-5 days) is generally sufficient 1
Complicated UTIs
- Longer courses (7-14 days) of antibiotics are required
- Culture-directed therapy is essential
- Parenteral therapy often required initially, especially for pyelonephritis 1
Inpatient Treatment
- Start with parenteral antibiotics
- Follow with culture-directed therapy for 7-14 days 1
Special Populations
Pregnant Women
- Recommended antibiotics:
- Nitrofurantoin
- Fosfomycin
- Cephalexin
- Avoid TMP-SMX in first and third trimesters 1
Postmenopausal Women
- Vaginal estrogen replacement strongly recommended for prevention of recurrent UTI 1
Elderly Patients
- Adjust antibiotic choice based on renal function
- Avoid nitrofurantoin if creatinine clearance <30 mL/min 1
Patients with Renal Impairment (CrCl <30 mL/min)
- Preferred: Fosfomycin 3g single dose
- Consider aminoglycoside with adjusted dosing if parenteral therapy needed 1
- For levofloxacin, adjust dosing:
- CrCl ≥50 mL/min: 500 mg once daily
- CrCl 26-49 mL/min: 500 mg once daily
- CrCl 10-25 mL/min: 250 mg once daily 1
Prevention of Recurrent UTIs
Stepwise approach starting with non-antimicrobial interventions:
- Increase fluid intake
- Vaginal estrogen replacement (for postmenopausal women)
- Immunoactive prophylaxis 1
Prophylactic antibiotic options:
- TMP-SMX 40mg/200mg once daily or three times weekly
- Nitrofurantoin 50-100mg daily
- Cephalexin 125-250mg daily
- Fosfomycin 3g every 10 days 1
Follow-up and Monitoring
Assess clinical response within 48-72 hours of starting treatment
If symptoms persist beyond 72 hours:
- Obtain urine culture
- Change antibiotic based on culture results
- Evaluate for complications or anatomical abnormalities 1
No routine laboratory monitoring required for short-course therapy 1
Important Considerations
Asymptomatic bacteriuria generally does not require treatment, except in pregnant women and high-risk patients with catheters 1
For penicillin-allergic patients, first-generation cephalosporins or clindamycin may be used 1
Antibiotics should be used only for proven or strongly suspected bacterial infections to reduce development of drug-resistant bacteria 2
Fluoroquinolones (like ciprofloxacin) are effective but should be reserved for more invasive infections due to resistance concerns 3
Recurrent UTIs can significantly impact quality of life, affecting social and sexual relationships, self-esteem, and work capacity 1
Antibiotic Dosing in Renal Impairment
- Ciprofloxacin dosing for renal impairment:
- CrCl >50 mL/min: Standard dosing
- CrCl 30-50 mL/min: 250-500 mg q12h
- CrCl 5-29 mL/min: 250-500 mg q18h
- Hemodialysis/peritoneal dialysis: 250-500 mg q24h (after dialysis) 4